Samara LynnWestern Digital WD Sentinel RX4100Western Digital's WD Sentinel RX4100 NAS offers SMBs very good performance, excellent data protection, and the power of Windows Server. But incompatibility with all but a few WD drives drags down its score.

Western Digital's WD Sentinel RX4100 NAS offers SMBs very good performance, excellent data protection, and the power of Windows Server. But incompatibility with all but a few WD drives drags down its score.

A NAS device that's perfect for consumer/SOHO users interested in streaming media just won't fill the bill when it comes to SMB usage, no matter how massive a chunk of storage it offers. You need a true business-class device for that, and that's where the Western Digital's WD Sentinel RX4100 ($1,899.99) comes in. The RX100 is a reliable four-bay SMB NAS, one that's best suited for Windows shops (though it does offer good Mac functionality, as well). That's because it uses Microsoft's excellent Windows Storage Server Essentials operating system to help your business manage all aspects of network storage. The RX4100 offers very good performance, incredible data protection, and all the benefits of Windows Server. I have one issue with this otherwise-excellent NAS: the very limited variety of hard drives it accepts.

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SpecsThe RX4100 is a surprisingly quiet 1U rack-mount device with two USB 3.0 ports on the rear panel and a single USB 2.0 port on the front. Other specs include dual Gigabit Ethernet ports, 4GB RAM, and an Intel Atom Dual Core 1.8GHz processor. It's available in three storage-size options: 8TB ($1,899.99, reviewed here), 12TB ($1,999.99), and 16TB ($2,349.99). The unit takes 3.5-inch SATA drives in the four drive bays on the front and supports RAID 5 configuration. Drives are simple to install and remove, thanks to a spring lever on each drive tray. The hard drives are of course, hot-swappable, but you can't just swap in any old 3.5-inch hard drive, I discovered. More on this in a bit.

Setup and Windows Storage ServerWindows Storage Server is installed by default. You just have to follow a few steps after boot up, such as setting the language and time, and then you're ready to go. Windows Server administrators will feel at home in the interface, which is where you perform most of your storage management. The Home screen of the dashboard has a helpful and organized to-do list to assist in server-configuration tasks such as setting up remote Web access, establishing sharing options, and more. On this same screen is the tab WD Guardian Services, which allows you to choose a support contract for the server, something that serious business users will likely want to do.

Some native Windows server components are also available via the dashboard. You can, for example, add users as well as manage computers and folder shares. Of course, since this is a Microsoft server, you can also join the server to an Active Directory domain.

A highlight in the software is how easy it is to set up iSCSI targeting. I created an iSCSI target and the system automatically assigned it a name (which is editable). It then prompted me to allocate the amount of space I wanted to assign to the target. The iSCSI wizard also provided the Portal Internet Protocol address, which I used to easily set up a Windows 7 machine as an iSCSI initiator. The often-complex process of configuring iSCSI targeting in NASes is made quite simple here. You can also elect to use Challenge-Handshake Authentication Protocol (CHAP) to secure communication between the target and initiators. If this is a bit beyond your networking knowledge, just know that all of this adds up to surprisingly easy setup of a small business storage area network (SAN), without you needing to run fiber throughout the office.

It's also very easy to connect a client machine to the RX4100 by pointing a browser to http://wdsentinel/connect and completing the wizard-based setup. I tested this procedure on a Windows 7 client system. I was required to download the WD Sentinel Computer Connector software to make the connection. This software is also available for Macs, so the RX4100 can function in hybrid environments, another plus.

With the connector software installed, my Windows 7 client became a remote storage server console. I was able to launch the Dashboard from my Windows 7 laptop and monitor the RX4100 and its backup jobs. More on backup below.

There are a few third-party apps available for the RX4100. KeepVault Online Backup is bundled into the Dashboard, though you do have to purchase a subscription to use it. Other add-ons include WD Mac Dashboard (which provides the administrator's Dashboard feature on Mac OS machines) and Windows Server Solutions Phone Connector (which enables you to connect to the storage server using your Windows phone).

Additionally, within the Dashboard, you can configure the backup of any Windows XP SP3 and later and Mac OS X 10.5 and later machines connected to the network. The RX4100 also integrates with Time Machine; again, this is a good choice for offices with both Windows systems and Macs.

Performance TestingTo test performance, I copied a 1.48GB file back-and-forth between the RX4100 and a Windows 7 client. The RX4100 supports RAID 5 configuration. The average write speed was 92.5MBps. That's a very good number, but not the best result I've seen from an SMB NAS. That nod still goes to Synology's DiskStation DS1813+, at 108MBps. Still, the RX100's 92.5MBps is an impressive result.

Read speed was nearly as quick, averaging 82.2MBps, a little above the DS1813+'s 72MBps. The Synology NAS has the processor advantage over the RX4100, thanks to a Dual Core 2.13GHz chip, but the RX4100 has the memory advantage—4GB versus 1GB, as tested. The Synology DS1813+'s memory is expandable up to 4GB, however, and Synology's NAS would likely significantly outperform the RX4100 if its memory were maxxed out. As its specs stand, however, it's clear that the hardware and software combined make the RX4100 a storage server fit for most SMBs, save for those with the most intensive I/O workload needs.

Rigid RAID RebuildsNext, I tested how well the NAS could bounce back from a drive crash. I pulled the drive from bay three. Red lights immediately flashed above that drive bay, and in the Monitor section of the Dashboard, the following alert appeared: "Your protection has been degraded but no data loss is detected."

So far, so good. I had the newest 6TB Western Digital Red drive on hand, so I popped it into the third bay, and got an incompatibility message. This for a brand-new hard drive, and one from Western Digital no less?

I tried a different drive, a Seagate. I got the same error message. I finally clicked on the list of supported drives, to find that it includes only five of the many, many hard drives that are regularly used in SMB NASes. Many current Western Digital drives don't even make the list. I also was presented with a link where I would purchase any of the five drives from WD's online store.

I have never swapped out a drive on a NAS and had it rejected because of its brand. The only times I've ever had drives rejected have been due to an insufficient capacity to hold the rebuilt volume. Can you imagine a server administrator under the gun to get a server that has crashed up and running, only to discover that she does not have one of the very few types of drives available to recreate a RAID volume and has to buy new ones, possibly by mail?

In all fairness, the server is capable enough that it's still accessible and usable in the event of a single-drive failure. That said, I still think it's lame that WD would put in such a severe HDD restriction.

SMB Excellence, With One CaveatWestern Digital's WD Sentinel RX4100 is a sure fit in an SMB data center. Just make sure to have compatible drives stashed in case you need to swap out a failed one. With iSCSI targeting and the ability to manage both Mac and Windows clients, the WD Sentinel is a relatively affordable way to bring a sophisticated SAN solution into a small business's infrastructure. It falls short of earning our Editors' Choice designation given that limited drive compatibility. For an excellent and more drive-agnostic SMB NAS, however, consider the Editors' Choice Synology DiskStation DS1813+.

Western Digital WD Sentinel RX4100

Bottom Line: Western Digital's WD Sentinel RX4100 NAS offers SMBs very good performance, excellent data protection, and the power of Windows Server. But incompatibility with all but a few WD drives drags down its score.

About the Author

Samara Lynn has nearly twenty years experience in Information Technology; most recently as IT Director at a major New York City healthcare facility. She has a Bachelor's degree from Brooklyn College, several technology certifications, and she was a tech editor for the CRN Test Center.
With an extensive, hands-on background in deploying and manag... See Full Bio

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Western Digital WD Sentinel RX4...

Western Digital WD Sentinel RX4100

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